[Nephets0]

Hey guys/gals.

my roomate has an 03 malibu that now has a permanent no start condition.
It started out as an every sunday thing, wont start after a few trips around town. now its broken down completely.

it has thrown a huge list of codes:
[PCM] P0128 - Coolant Thermostat (SES) (Old) (History) (Immature)
[PCM] P0420 - Catalyst System Low Efficiency (SES) (Old) (History) (Current) (Immature)
[Unknown] B2585 - (SES)
[Unknown] B2577 - (SES)
[Unknown] B2575 - (SES)
[Unknown] B2578 - (SES)
[Unknown] B2587 - (SES)
[Unknown] B2588 - (SES)
[Unknown] B2648 - (SES)
[Unknown] B2600 - (SES)
[Unknown] B2601 - (SES)
[Unknown] B2602 - (SES)
[Unknown] B2603 - (SES)
[Unknown] B2965 - (History)
[Unknown] B2958 - Security System Sensor Data Circuit High (History)
[Unknown] B1001 - Option Configuration Error (SES)

So far we've checked power and ground distribution. Everything seems alright. This weekend we are going to troubleshsoot the B2965 and B2958. We have tried a new ignition switch. that was a straight no go. we tried the passlock relearn procedure multiple times for an hour and a half with the new switch and the old switch.

Anyone got any suggestions at this point?

 

[RickSteen]

OMG man....personnaly i think your A/T computer is completly melted, go to chevy dealer and ask for reprogrammation of theft system, it's cheap and sometime it solved a lot of troubles

P0128 : just change your thermostat, it will solve the problem
P0420: Catalyst System Efficiency Below Threshold (Bank 1) H02 sensor detect a backflow, you cat is probably clogged at the input.

all B*** are anti-theft trouble codes. and with this quantity of dtc, your system is probably defective.

my conclusion: your car won't start because it act like if someone tried to steal the car.